Book Image

Learning Apache Flink

By : Tanmay Deshpande
Book Image

Learning Apache Flink

By: Tanmay Deshpande

Overview of this book

<p>With the advent of massive computer systems, organizations in different domains generate large amounts of data on a real-time basis. The latest entrant to big data processing, Apache Flink, is designed to process continuous streams of data at a lightning fast pace.</p> <p>This book will be your definitive guide to batch and stream data processing with Apache Flink. The book begins with introducing the Apache Flink ecosystem, setting it up and using the DataSet and DataStream API for processing batch and streaming datasets. Bringing the power of SQL to Flink, this book will then explore the Table API for querying and manipulating data. In the latter half of the book, readers will get to learn the remaining ecosystem of Apache Flink to achieve complex tasks such as event processing, machine learning, and graph processing. The final part of the book would consist of topics such as scaling Flink solutions, performance optimization and integrating Flink with other tools such as ElasticSearch.</p> <p>Whether you want to dive deeper into Apache Flink, or want to investigate how to get more out of this powerful technology, you’ll find everything you need inside.</p>
Table of Contents (17 chapters)
Learning Apache Flink
About the Author
About the Reviewers
Customer Feedback

Monitoring REST API

Flink supports the monitoring of the status of running and completed apps. These APIs are also used by Flink's own job dashboard. The status APIs support the get method which returns JSON objects giving information of the job. Currently, monitoring APIs is by default started within the Flink Job Manager dashboard. This information can also be accessed with Job Manager Dashboard.

There are many APIs available in Flink. Let's start understanding some of them.

Config API

This gives configuration details of the API:  http://localhost:8081/config

The following is  the response:

    "refresh-interval": 3000, 
    "timezone-offset": 19800000, 
    "timezone-name": "India Standard Time", 
    "flink-version": "1.0.3", 
    "flink-revision": "f3a6b5f @ 06.05.2016 @ 12:58:02 UTC" 

Overview API

This gives an overview of the Flink cluster: http://localhost:8081/overview

The following is the response:

    "taskmanagers": 1,